Flatten BigQuery JSON schema

flatten_schema.py

import click
import json


@click.command()
@click.argument("input_source", type=click.File("rt"))
def flatten(input_source):
    """
    Creates a flattened representation of a BigQuery JSON schema.

    \b
    :param input_source: A JSON schema file or STDIN
    :return: Streams flattened data to STDOUT
    """
    schema = json.load(input_source)
    _process_array(schema)


def _process_array(ary, parent=None):
    for element in ary:
        name = '.'.join([i for i in [parent, element["name"]] if i is not None])
        print("{0:<65s} {1:<12s} {2:s}".format(name, element["type"], element["mode"]))
        if element["type"] == "RECORD":
            _process_array(element["fields"], parent=name)


if __name__ == "__main__":
    flatten()